Sodium cromoglycate (1,3-bis(2-carboxychromon-5 -yloxy)-2-hydroxypropane sodium salt) is known as a substance for regulating release of chemical mediators from mast cells upon type I allergic reaction, and used in treatment of allergic diseases such as allergic asthma by administering inhalation capsules, inhalation solution or aerosol preparation thereof through inhalation. Japanese Kokai Publication Sho-52-44242 discloses that sodium cromoglycate is used in treatment of chronic skin diseases and eye diseases attributable to allergic or immune reaction by topical administration thereof into skin or optic tissues. Japanese Kokai Publication Hei-11-335281 and Japanese Kokai Publication Hei-11-335282 disclose that an external preparation containing sodium cromoglycate is effective in treatment of skin diseases such as dry skin.
However, the therapeutic effect of the external preparation containing sodium cromoglycate in treating skin diseases was not necessarily sufficient.